Before you rush to create long filenames for the files in your web, stop for a moment to consider whether you'll ever need to demonstrate the web on an IBM-compatible computer offline. If you will, then you had better restrict yourself to eight character (max) filenames and three character (max) file extensions, and ensure that no two files in your web are distinguished by case only.
Even if you won't need to run your web on a PC, it's wise to choose filenames that can be easily ported to different kinds of servers. Here are some "safe filename" rules:
Identifier of 8 Keep the filename identifier (e.g. sloth in sloth.dat) to 8 characters or less. Reason: Some operating systems, including MS-DOS, do not support identifiers of more than eight characters.
Extension of 3: Keep the filename extension (e.g. dat in sloth.dat) to 3 characters or less. Reason: Some operating systems, including MS-DOS, do not support extensions of more than three characters.
Always use an extension for all non-directory files: Always use an extension for all non-directory files, even under Unix. For example, name your file sloth.txt rather than just sloth. Reason: When moving from operating systems that do not have a formal extension to those that do, a dot will be added to the end of the filename. For example, sloth will become SLOTH.. However, sloth.txt will become SLOTH.TXT.}
Do not use an extension for directory files: For directory files, use the compulsory extension (e.g. .DIR if it is required (e.g. under VMS), or no extension if it is not required (e.g. under Unix)). Reason: If you call a Unix directory my.stuff, then problems will arise when this directory has to be transferred to an operating system that insists on directory extensions of .DIR. How do you represent my.stuff.DIR in a filename format that disallows more than one dot?
Use at most one extension: Use at most one extension in your filename. Filenames such as archive.tar.Z do not port well to operating systems such as VMS that can cope with only one dot in a filename.
Use only lower case on Unix: Don't use upper case letters in your Unix (or Macintosh) filenames. If you get in the habit of using them, there's a chance you might create two files whose names differ only by case. Another reason for using lower case is that some cross-mounting systems work better when the Unix filenames are in lower case.
Use only letters, digits, dots, and underscores: Use only letters, digits, dots, and underscores in your filenames. Other characters may not be supported by other operating systems. In particular, do not include spaces in your filenames (as is common in Macintosh filenames) as these are definitely not portable.
Of these restrictions, the only restriction that is really a
nuisance is the
eight-character limit on identifiers. This can be ignored if you do
not intend to ever move your files to an MS-DOS machine. But be aware that
the next length limits on the identifier is 15 for System-V Unix, 31
for the Macintosh, and 39 for VMS.
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